Inorganic-organic synthetic materials based on polyisocyanates and aqueous alkali metal silicate solutions are already known and are described, for example, in German Offenlegungsschrift 1,770,384; U.S. application Ser. No. 527,476 now U.S. Pat. No. 4,097,423, filed Nov. 26, 1974, U.S. application Ser. No. 527,478 now abandoned, filed Nov. 26, 1974, and U.S. Pat. Nos. 3,965,051, 3,981,831, 3,985,929, 4,042,536 and 4,052,347.
It is possible in this way to produce synthetic materials which, by virtue of their inorganic content, are more fire resistant than purely organic materials particularly in their fire resistance. They may be foamed or unfoamed, hard or soft, brittle or flexible materials, depending upon their composition and the reaction conditions. These inorganic-organic synthetic materials are suitable for a wide range of possible applications, because of the great variability of their properties.
Common to all of these materials in the fact that to produce them, the organic phase and the inorganic phase must be mixed together. W/O (water-in-oil) or O/W (oil-in-water) dispersions are thereby formed. Those synthetic materials which are obtained from a W/O type of dispersion are particularly interesting. They have high mechanical strengths even when exposed to moisture because the hardened, continuous organic phase envelops and thereby fixes the aqueous, inorganic discontinuous phase which is also hardened. The improved fire resistance of such systems also depends on the perfectly continuous organic phase of these materials, due to the water enclosed by this phase.
Attempts have been made to produce the synthetic materials described above by mixing the reactants in an intermittently or continuously operating mixing apparatus in either one or more stages and then leaving the resulting dispersion to solidify.
Thus, according to U.S. Pat. No. 4,042,536, for example, mixing of
(a) an organic polyisocyanate, PA1 (b) an aqueous silicate solution and PA1 (c) an organic component PA1 (a) an organic polyisocyanate, PA1 (b) an aqueous basic solution and/or an aqueous basic suspension having an inorganic solids content of from 20 to 80% by weight, and preferably from 30 to 70% by weight, PA1 (c) an organic compound containing at least one isocyanate reactive hydrogen atom and at least one non-ionic hydrophilic group and PA1 (d) optionally catalysts and other additives PA1 (1) Two agitators with mixing heads; PA1 (2) Two mixing assemblies consisting of two mixing devices mounted one after the other on a driven shaft, components (a) and (b), and optionally (d), being fed in at the top end of the driven shaft and component (c), and optionally (d), in the lower part of the shaft; PA1 (3) Mixing assemblies consisting of two static mixing apparatus arranged one behind the other; components (a) and (b), and optionally (d), being fed into the first static mixer and, after passing through the first mixing path, they are mixed with component (c), and optionally (d), in the second static mixer; PA1 (4) An agitator with mixing head as first mixing apparatus and a static mixer as second mixing apparatus; and, PA1 (5) A static mixer as the first mixing apparatus and an agitator with mixing head as the second mixing apparatus.
is carried out by first preparing a preliminary mixture of (b) and (c) or by mixing (a), (b) and (c) all together.
This method, however, frequently gives rise to products which have increased degrees of defects as the proportion of organic component increases. In the extreme case, the formation of a regular structure of an inorganic-organic synthetic material may be prevented.
It is an object of the present invention to obviate the disadvantages described above and to provide a process by which inorganic-organic synthetic materials can be produced problem-free even with high proportions of organic constituents.
These problems are solved by the process according to the invention.